Počet záznamů: 1

Gluon-spin contribution to the proton spin from the double helicity asymmetry in inclusive pi0 production in polarized p + p collisions at s**(1/2) = 200 GeV

  1. 1.
    0345166 - FZU-D 2011 RIV US eng J - Článek v odborném periodiku
    Adare, A. - Afanasiev, S. - Aidala, C. - Růžička, Pavel - Tomášek, Lukáš - Vrba, Václav
    Gluon-spin contribution to the proton spin from the double helicity asymmetry in inclusive pi0 production in polarized p + p collisions at s**(1/2) = 200 GeV.
    Physical Review Letters. Roč. 103, č. 1 (2009), 012003/1-012003/4 ISSN 0031-9007
    Grant CEP: GA MŠk LA08015
    Výzkumný záměr: CEZ:AV0Z10100502
    Klíčová slova: PHENIX * gluon * proton spin
    Kód oboru RIV: BF - Elementární částice a fyzika vys. energií
    Impakt faktor: 7.328, rok: 2009
    http://arxiv.org/pdf/0810.0694 http://arxiv.org/pdf/0810.0694

    he double helicity asymmetry in neutral pion production for p_T = 1 to 12 GeV/c has been measured with the PHENIX experiment in order to access the gluon spin contribution, Delta-G, to the proton spin. Measured asymmetries are consistent with zero, and at a theory scale of /mu^2 = 4 GeV^2 give Delta-G^[0.02,0.3] = 0.1 to 0.2, with a constraint of -0.7 < Delta-G^[0.02,0.3] < 0.5 at Delta-chi^2 = 9 (~3 sigma) for our sampled gluon momentum fraction (x) range, 0.02 to 0.3. The results are obtained using predictions for our measured asymmetries generated from four representative fits to polarized deep inelastic scattering data. We also consider the dependence of the Delta-G constraint on the choice of theoretical scale, a dominant uncertainty in these predictions.
    Trvalý link: http://hdl.handle.net/11104/0186495